An already wobbly week for House Republicans turned chaotic Thursday as their unruly new majority flatly rejected a spending plan crafted by House leaders, saying its cuts fell far short of fulfilling a campaign pledge to slice $100 billion from federal programs.

House leaders offered to redo the package but were struggling to identify the massive and unprecedented cuts that will be required to meet their goal. Dissatisfied conservatives, meanwhile, were pressing for even sharper reductions that could prove difficult to push through the House, much less the Democratic-controlled Senate.

The uprising exposed serious divisions among Republicans bent on reducing the size of government, the defining issue of the campaign that swept them back into power in the House this fall. Dozens of freshmen, fueled by tea party fervor, are demanding a rapid response to the groundswell of public anger.

"As important as these spending cuts are, we need a lot more than we're getting served up today," Bachmann said to cheers at the Marriott Wardman hotel.

Establishment conservatives also weighed in. The anti-tax Club for Growth and Heritage Action for America, a group associated with the Heritage Foundation, announced that they will make the spending plan a "key vote" in their congressional rankings, downgrading lawmakers who support anything short of the strictest interpretation of the $100 billion pledge.

"It's important that the new majority demonstrate that they can fulfill their promises," said Mike Connolly, a spokesman for the Club for Growth, which was instrumental in electing more than a dozen of the 87 GOP freshmen.

"The pledge House Republicans made to the American people was to cut $100 billion from the president's budget request. Economists and accountants can come up with different ways to do anything, but it was pretty clear what was meant," Connolly said. "All we're asking is that they fulfill the pledge."

The spending dispute was the most consequential in a series of missteps by House leaders this week, including two failed votes on bills to extend the USA Patriot Act and rescind funding from the United Nations. House Republicans were also forced to delay a vote on a measure that would reauthorize a program that provides assistance to people who lose their jobs to foreign imports.

Capping it all off was the resignation of a married second-term Republican from New York who was caught flirting with a woman on Craigslist.

The definition of the $100 billion pledge - a cornerstone of the campaign that produced the biggest midterm landslide since 1938 - is proving increasingly troublesome. In their "Pledge to America," Boehner and other GOP leaders vowed to immediately restore federal spending to 2008 levels, a time before Obama took office and ramped up spending to combat the worst recession since the Great Depression.